The research and development of polymer material has been a hot topic conducted by scholars in many countries for many years. Ion irradiation can cause changes in microstructure and macro-performance of material, so it can be used in the research on transforming polymer material. In the early phase, low ionizing radiation particles (such as Gamma ray, electron and so on) were mainly used as irradiation source. Studies found that the irradiation could generate effects in the polymer, mainly including fracture and cross-linking of molecular bond, release of gas molecule and formation of new chemical bond. The fracture and cross-linking of molecular bond could change molecular weight of material and its distribution, thus affecting the macro-performance of material. In general, the cross-linking of molecular chain could increase the molecular weight and reduce solubility and absorbance of the biomaterial. These phenomena triggered by low ionizing radiation had been fully researched and had been widely used in business application. In material, heavy ions lose energy mainly through ionizing and stimulating electrons of the target atom. Unlike low ionizing radiation particles, the heavy ions have very high electronic stopping power (linear energy transfer value LET), so heavy ions cause charge transfer and energy deposition. Consequently, when ions pass through medium, a continuous columnar ionization area can be left along its path, thus generating cross-linking and forming stable complex without causing loss of biological activity. This effect provides a method for researching complex in biological medicine.
Hypericin is a main active ingredient substance of Hypericum perforatum L., a guttiferae hypericum, and its structure belongs to naphthyl dianthrone compound. By virtue of its antiretroviral effect in vivo and in vitro and extremely strong anti-virus, antisepsis and anti-inflammation effects, hypericin can activate mononuclear phagocyte and strengthen immunity of the organism of poultry.
Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS had conducted extraction, chemical synthesis and veterinary clinical application related to hypericin, thus making the application of hypericin products in veterinary diseases more widely. Through clinical trials in vivo and in vitro, the curative ratio for yellow scour and white scour of newborn pigs and pullorum disease caused by Escherichia coli is over 95%. Targeting preparation, also known as targeting drug system (TDS or targeted drug delivery system, TDDS), is a new drug delivery system that could concentrate and locate drugs at lesion tissue, organ, cell or intracellular structure. Targeted therapy could significantly increase drug concentration of treated areas, decrease drug dosage, lower treatment costs, and reduce toxic side effect of drugs on the whole body. At present, targeting preparation is mainly used in cancer drugs of humans and no veterinary usage in clinic is reported. The inventors of the present invention conducted cross-linking combination of Chinese medicine ingredient hypericin with antibody and ethanediol through heavy ion irradiation to build “biological missile”, thus conducting research on implementing “precise strike” to pathogenic bacteria. Results of the present invention showed that low dose of carbon ion irradiation could cause cross-linking of bio-molecules without affecting their structures and activities. The utilization of heavy ion cross-linking technology provides a new pathway for cross-linking of bio-molecules.